Fluid pump



Jul1'9, 1940-l 2 B. F. SCHMIDT 2,207,226

Y-RI

Patented July 9, 1940 .UNITED STATES PATENT: oFFIcr.

FLUm PUMP Benjamin F. schmidt, Les Angeles, cam. Application January 1s, 193s, sei-iai No. 185,531

8 Claims.

My invention relates to uid pumps and has particular reference to pumping apparatus particularly adapted for 'the pumping of uids in either gaseous or liquid state.

In piston and cylinder types of fluid pumps, considerable diiilculty is encounted in preventing undue wear between the piston and cylinder walls, particularly when the pump is employed to pump fluids containing abrasive material such as sand. grit or dust.

It is therefore an object of my invention to provide a pumping apparatus of the piston and cylinder type in which the fluid to be pumped is maintained out of contact with the piston.-

Another object of my invention is to provide a pump of the character set forth wherein the piston operates in a bath of oil or similar lubricating 'uid, which bath acts either alone or in combination with other liquids as a uid piston in contact with the uids to be pumped by the device.

Another object of my invention is to provide a piston of the character set forth in the preceding paragraph wherein air or gases which may be entrapped between the lubricant liquid piston and the metal piston may freely escape and in which any of the lubricant llquid which passes between the piston and cylinder walls is automatically replaced. between the piston head and the fluid to be pumped by the device.

Another object of my invention is to provide a pump of the character set forth in which a metal piston operating within a. cylinder is separated from the fluid to be pumped by the device by a liquid column extending between the head of the piston and the fluid to be pumped by the device and in which the column of fluid may be varied to vary the compression ratio ofthe apparatus tallic piston employed may be formed as a com pound piston including two piston sections coupled to the same crank shaft, each movable through a different length of stroke to assist in obtaining a high degree of compression with a minimum of applied power. v

Another object of `my invention is to provide a pumping device of the character set forth where- (Cl. S-165) in intake and exhaust valves are provided upon. a removable mounting means by which the valve assembly may be readily removed for repair or replacement.

Other objects and advantages of my invention will be apparent from a study of the following specifications, read in connection with the accompanying drawnigs, wherein Fig.,1 is a diagrammatic vertical sectional viewf taken through a pumping apparatus constructed in accordance with my invention;

Fig. 2 is a detail vertical sectional view taken through the piston and cylinder assembly shown in Fig. 1 along line II-II of Fig. 1;

Fig. 3 is a vertical sectional view of a modied compression chamber which may be substituted for the .compression chamber shown in Fig. 1;

Fig. 4 is a plan view of the valve and valve mounting assembly shown in Fig. 1;

Fig. I5 is a vertical sectional view similar to Fig. l and illustrating a modified form of pump embodying the principles of my invention, par# ticularly adapted for compressing air and similar gases;

Fig. 6 is a detail vertical sectional view of a fluid injector which may be associated with the pistons of the pumps shown in either Figs. 1 or 5; and

Fig. '7 is a fragmentary detail view of a modified form of piston and cylinder construction which may be employed in the practice of my invention.

Referring to the drawings, I have illustrated in Figsl 1, 2 and 4 one form of my pumping. appavratus which is particularly adapted to the pumping of fluids containing or exposed to grit, sand or other solid material, such as the pumping of mud iiuicl in oil Well drilling practice. The p ump comprises a suitable bed or support I which may l be constructed of any suitable material such as I beams and the like to constitute a mounting upon which a pump frame 2 may be secured as by means of bolts 3.. 'Ihe frame 2 preferably includes bearings 4 and 5, in whichis journaled a crank shaft 6 which is adapted to be rotated in any suitable manner from power apparatus which may apply rotative power to a pulley 'l and which at any desired speed.

Attached to the pump frame 2 is a cylinder l0 in which is adapted `to operate a metallic pump, piston Il. The piston may be of any suitable construction havingrings `I2 or other packing material to insure sealing engagement between the walls of the cylinder and the walls of the through gears 8 and 9 rotates the crank shaft 6 piston. By referring particularly to Fig. 2, it will be observed that the piston II is hollow as indicated at I3 to provide a chamber into which projects one end I4 of a connecting rod I5 and within which the connecting rod is secured to a suitable wrist pin I6, the opposite end of the connecting rod I5 being secured upon the crank pin Illl .of the crank shaft 6 in any well known manner, as indicated at I8.' It will be noted that the operating head or outer face I0 of the piston ii is directed downwardly and that upon each down stroke of the piston it will compress or drive out of the cylinder I 6 any uid which may be contained within the cylinder below the piston head I9.

As illustrated in Fig. 1, the cylinder III is adapted to be filled with oil or other lubricating uid 20, a conduit 2| extending from the head 22 (that is, the bottom end of the cylinder III) to a pumping chamberv 23 which is preferably disposed at a slightly lower level than the level of the cylinder I6 while the conduit 2| is provided with a bend 24 near its lowermost portion to con-- stitute a trap 25 which will act to trap uids interposed between the cylinder I0 and the pumping-chamber 23. Y

When my pumping apparatus is to be employed for the pumping of mud or similar fluids containing grit or debris, I provide a quantity of mercury 26 in the pumping chamber 23, the

amount of mercury contained therein being` preferably insuiiicient to pass'upwardly into the cylinder I0 on the up stroke of the piston II. Mercury and oil, being non-miscible liquids, will maintain a line of separationbetween themselves as indicated at 21 so that upon each stroke of the piston I0 the piston will operate only against l a head of'oil or similarlubricating liquid, while the mercury will constitute-a fluid piston in con-4 tact with the fluid to be Dumped and effectively preventing any contact between the gritty substances and the walls of the piston and cylinder and hence the rapid abrasion of pistons and cylinders commonly found in pumps employed. for this purpose is avoided.

During the operation of the piston Il some quantities of oil or lubricating iluid 26 will leak past the piston walls into the upper end of the cylinder I0. However, any such oil which may leak past the piston II will be trapped in a recess 28 surrounding the piston Il and will fall by gravity through ports 29 into the hollow portion I3 of thepiston, the lower wall 36 of which is so shaped as to drain any iiuid trapped in the hollow portion of the cylinder into a sump 3l. A force pump 32 is mountedin the sump 3| and is arranged in such manner as to forcibly eject any fluid in the sump 3l back to the lower end oi* the cylinder I0. v

One form of force pump which may be einployed for this purpose is illustrated in Fig. 2 and comprises a tubular jacket 33 threaded as at 34 into the sump 3| and provided with a plurality of openings or ports 35 communicating with the sump at the lowermost portion of the wall 36. The jacket 33 constitutes a pump barrel in which a plunger 36 operates, the plunger being secured upon the lower end o a plunger rod 31 which extends upwardly through acover A38 on the `jacket 33 andterminates in al shoe`33 adapted engaged by the bracket 40 and will cause relative downward movementof the plunger 36l within`its aad/,22a

cylinder or jacket 33. I prefer that the plunger 33 shall remain inactive during a considerable portion of the upstroke of the piston II so that onlyduringthe last portion of the Iupstroke is the plunger 36 depressed in the jacket 33. A spring 4I may be employed to normally hold lthe plunger in an elevated position as shown in Fig. 2, except when the shoe 39 is engaged by the bracket 40. A

A ball valve 42 is preferably provided at the lower end of the sump 3I so that during the down stroke of the piston there will be no leakage of the oil or lubricating fluid 20 upwardly through the lubricating Aliquid I9 but upon the up stroke of the piston I I any iiuid which may be trapped in the sump will be forcibly ejected therefrom past the ball valve.

I preferably select the volumetric design of the force pump 32 such as to be capable of pumping upon each of its strokes a greater quantity of uid than would normally leak past the cylinder walls and hence provision should be made to pre'- vent the pumping or forcing of air into the cylinder I0 as the force pump is operated and for this purpose I have provided the plunger 36 with a hollow interior and have provided ports 43 com.4 municating .through the upper endof the plunger 36. The ports 43 are adapted to be closed by a. buoyant valve member 44 normally supported upon a pin 45 in the hollow plunger 36 in spaced. relation to the ports 43. However, upon a down,

stroke of the p1unger`36 any air or other gases which may be located below the plunger 36 will be permitted to escape through the pforts 43 until the plunger encounters liquid, at which time thebuoyant valve member 44 will float upon the surface of the liquid and' will be moved upwardly into sealing engagement with they ports 43 and thereafter further downward movement of the plunger 36 willeject the liquid through the 'ball valve 42.

By employing a uid mercury piston 26 in the pump chamber 23 it will` be apparent that sufilcient sealing contact will be made between the mercury and the walls'of the chamber 23 to prevent thetrapping of gritty fluids therebetween and hence little or no wear will be apparent upon the wall of the chamber 23 after relatively long periods of use, though I prefer that the interior of the lchamber 23 be coated with a coating 46 of suitable metals such as silver or tin or other metal which will co-act with the mercury to form an amalgam and provide a wiping contact therebetween, preventing the collection or building up of mud or any similar substance on y the walls of the chamber 23.

-with poppet Valves 50 and 5'I, respectively,-

adapted to open or close dependent upon the direction of movement offthe fiufd piston 26. By employing this character of valve and valve mounting structure, the inlets andoutlets for the mud or other uid to be pumped may be readily mounted upon the pump chamber 23 as by providing a suitable manifold 52 having a partition wall 53 therein adapted to-seat along one of the diameters of the valve mounting plate l1 and to which it may be secured by means of bolts 54, the casting being provided with an inlet passage 55 communicating with a pipe or` conduit 56 and with an outlet passage 51 cornmunicating with an outlet pipe 56.

It will be observed therefore that I have provided a pump in which the metallic parts ofthe cylinder and piston are constantly operating ina bath of lubricating liquid and hence are subjected to a minimum of wear and abrasion while the fluid piston which is in actual contact with the fluid tobe pumped is of such character as to reduce any abrasive action of the fluid to a minimum.

As shown in Fig. 1, several pump units as hereinbefore described may be mounted upon a single base I as by providing extensions of the pulley such .case I may use an auxiliary piston mechanism as shown in Fig. 3. In this form of the device the pumping chamber 23a is provided with vertically extending cylindrical walls plated as indicated at 46a with material capable of amal-` gamating with mercury, a quantity of mercury 26a constituting the fluid piston contained therein. Floating upon the top of the mercury piston 26a is an auxiliary .piston comprising a plate 62 having a diameter just slightly less than the diameter of the pump chamber 23a. 'I'he plate 62 is preferably secured to a guide stem 63 which operates in a guide bore 64 formed in the lower end of the pump chamber defining member. If desired, the plate 62 may also be plated or coated with a suitable metallic coating 62a similar to the plating or coating 46a.

- While the pump' construction illustrated in Figsyl through 4 is particularly adapted for the pumping of gritty fluid such as mud and the like, it will also be apparent that' the employmentof the fluid piston 26 also provides a ready means for pumping other liquids and gases.v For example, in desert locations or other places wherein the temperature of the surrounding atmosphere is relatively high, considerable diiliculty is encountered in compressing air sufiiciently to operate air actuated tools. My pumping mechanism is particularly adapted fo'r the compressing of air under these circumstances'in View of the fact that as the temperature of the air rises the merditions are not encountered, the employment of,

my uid piston type of pump for the pumping or compressing of gases is found to be l[very advantageous in that the compression ratio -of' the pump may be readily varied by introducing greater or lesser quantities of mercury into the purnp chamber 23, bringing the upper surface of the mercury into more or less close position relative to the valve structure l1-5l.

It will be understood by those skilled in this art that while, as illustrated herein, the liquid piston comprises oil and mercury, other liquids may be substituted therefor such as, for example, the entire liquid piston may be formed by a single liquid such as oil or water or other liquid which is non-miscible with the fluid to be pumped or the liquid piston may be formed of oil and water. the oil being disposedadj-acent the metallic piston and the water being disposed in the pump chamber, it being understood however thatin all cases in which the liquid piston is comprised of more than one iiuid the cylinder and pump chambers should be disposed eitherupon such different levels or the quantity ofthe heavier iluid should be such as to extend sumciently through the passageway between the cylinder and pump chamber that during normal pumping operations of the pump the several liquids will always maintain their same relations to each other, that is, under' no conditions should the stroke of the pump be such as to allow the Afluid in contact with the metallic piston to pass suiliciently into the pumping chamber to rise to the surface ofv or 'oat upon the portion of the liquid piston disposed in the pump chamber. f

It will also be noted that while as illustrated herein the liquid piston will be reciprocated through its cycle upon each cycle of movement of the rigid metallic piston Il, other means for reciprocating the liquid piston may be substituted which will alternately depress and elevate through 4. In this modification the pump frame,

cylinder and pump chamber are formed integrally as by castinga cylinder member Illa and a pump chamber member 23a upon a single base frame 2a. Intercommunicating with the cylinder' mem.- ber loa, I provide a fluid passage10, enabling the free passagebetween the cylinder lila and the pump chamber 23a of the uid piston formed by mercury as indicatedlat 2Gb. Interposed between the head 19a of thepiston lia and the mercury 26h is a .quantity of oil or similar lubricating fluid 20a-so that, as was described with reference to Figs. l through 4, the piston will operate continuously in a bath of lubricating fluid. A valve assembly simil-ar to that in Fig. 1 vmay be employed, comprising a mounting plate 41a upon which poppet valves 50a and Sla are mounted.

In Fig.'6 I have illustrated a slightly modified form of 'force pump which may be employed with either the pump shown in Figs. 1 through 4 .or with the formof the pump illustrated in Fig. 5, it being understood that the sump 3| in the piston l lcommunicates through the ball valve -42 in the same manner as described with reference to Fig. 1 through 4. The force pump `jacket 33 constitutes a cylinder in which operates a plunger 36a, the plunger being formed with an inwardly extending recess 1I formed at its lower end which communicates throughsuitable ports 12 with a tubular plunger operating stem 13 extending through the cover 38a on the jacket 33. Operating in the recess 1| is a substantially iiat disc plunger 14 mounted upon a stem '15 and normally held in spaced relation to the ports 12 by V"means of a spacer spring "16 which when normally extended, as shown in Fig. 6.' permits the ldisc plunger 14 to be separated from the ports 12. The tubular lstern 13 may be provided withia shoe (not shown) corresponding to the shoe 39, while a spring 4| normally urges the en- Working within the other.

tire plunger. assembly upwardly in the same manner as was described with reference to `the plunger 36. In this form of the device the initial downward movement'of the plunger 36a will permit any air or othergases to escape through the ports l2 and upwardly through the hollow stem 73, from which it may escape through outlet ports TI, while as. soon as the plunger descends sufficiently to contact the oil orother fluid 28, the liquid will raise the disc plunger 14 to a position closing the ports 'l2 and thereafter all of the force 'ofthe plunger 36a will be directed to ejecting the liquid past the ball valve 42.

In Fig. 7 I have illustrated a modified form of metal piston which may be employed in the practice of my invention with any of the forms of the device shown in Figs. 1 through 6, lthis modified form of piston mechanism being particularly adapted for the pumping of relatively large volumes of gases or other'fluids at relatively "low pressures with a minimum of applied eort.

In Fig. 7 I have illustrated a form of cylinder Illa corresponding to the cylinder Illa lshown in Fig. 5,' the upper walls of which extend as indi'- cated 'at 80 and 8| to constitute bearings for a crank shaft 82. In this form of the device the piston is` illustrated as comprising an outer piston member 83 and an'inner piston member 84, one The inner piston 84 is connected by means of a connecting rod 85 to a crank pin 88 having a relatively long throw so as to produce a relatively long rstroke of the piston 84 upon each revolution of the crank shaft 82, while. the piston member 83 is secured by means of connecting rods 81 and 88 to eccentric straps 89 and 80, respectively, which in turn operate upon eccentrics 9| and 92 rmed upon the crank shaft 82, the throw of `each f the eccentrics 9| and 92 being relatively short as compared with the throw of the crank pin. 86. v

It follows therefore that upon rotation of the crank shaft 82, the inner piston 84 will slide with- `in the outer piston 83 through' a relatively long stroke and will accomplish the major portion of the pumping or compressive action (it being understood that the lower ends of the pistons 83 and 84 will engage a bath of oil in the lower end of the cylinder Illa in the same manner as was described with reference to Figs. 1

-through Now as the connecting rod approaches a dead center position, the amount of vertical travel of the piston 84 is reduced to a minimum though the vertical component of the force exerted by the crank pin 86 at this time is at an extremely high value. By so locating the eccentrics 9| and 92 upon the crank shaft 82 that they tendto move the piston member 83 downwardly at a slower rate than the rate of movement of the piston 84, the latter portion of the movement'of the 'crank shaft 82 as it approaches a dead center position will move both pistons 84 and 83 downwardly through the final portion of .their stroke with extremely' high compressive force without requiring the addition o'f any appreciable amount of effort required to rotate the crank shaft 82.

With this form of the device I am enabled to employ a piston of relatively large area by combining the areas of the piston members 83 and 84. and providing)- the smaller piston 84 with a relatively long. stroke to perform the major portion of the work while the outer piston member 83 will assist and add to the effects of the movement of the piston 84 by providing a relatively short but effective final stroke, accomplished by a piston assembly of large area.

It will therefore be observed that I have provided improved pumping mechanisms particularly adapted for many pumping uses and particularly adapted for the pumping oi fluids having a high expansion coeiiicient under changes of temperature and particularly adapted for the pumping of fluids containing abrasive substances.

While'I have shown and described the preferred embodiments of my invention, I do not desire to be limited to any of the details of construction shown or described herein, except as defined in the .appended claims.

l. In a uid pump, means defining a cylinder and a pump chamber spaced from each other and interconnected by a fluid passage, a' metallic piston reciprocably mounted in said cylinder, inlet and outlet means for fluid to vbe pumped communicating with said pump chamber, a liquid column interposed between the outer face of said metallic piston and said pumpichamber to I provide a liquid piston in the pump chamber preventing the fluid to be pumped from contacting the metallic piston and its cylinder walls, liquid return means for returning to said liquid column any liquid which may leakpast said metallic piston, including a force pump actuated by reciprocation of said piston in said cylinder and intercommunicating between opposite faces of said metallic piston including an auxiliary cylinder, a plunger operated therein, means for reciprocating said plunger in said auxiliary cylinder, gas escape .ports in said plunger, and a oat valve on said plunger to close said ports only when said plunger is brought in contact with liquid.

2. In a fluid pump, means defining a.V cylinder and a pump chamber spaced from each other and interconnected by a fluid passage, a metallic piston reciprocably mounted in said cylinder, inlet and outlet means for iiuid to be pumped com. municating with said pump chamber, aliquid column interposed between said metallic piston, and said pump chamber including 4a column of oil adjacent said metallic piston, to provide a bath of lubricant in which said metallic piston operates and to provide a liquid piston in the pump chamber preventing the uid to be pumped from contacting the metallic piston and its cylinder walls, and 'a force pump for returning to said column any liquid which may leak past said metallic piston, said force pump having a volumetric capacity in excess of the maximum Volume of leakage on each stroke of said metallic piston to insure return'of all the liquid to the column.

3. In a uid pump. means denlng a cylinder and a pump chamber spaced from each other and interconnected by a fiu'id passage, a metallic piston reciprocably mounted, in said cylinder, inlet and outlet means for iiuid to be pumped communicating with said pump chamber, a liquid column .interposed between said metallic piston and said pump chamber including a column of oil adjacent said metallic piston, to provide a bath of lubricant in which said metallic' piston operates and to provide a liquid piston in the pump chamber preventing the uid to be pumped from contacting the metallic piston and its cylinder walls, and a force pump communicating with said cylinder on opposite sides of said metallic piston for.returning,to said column any liquid which may leak past said metallic piston.

'zol

said forcepump comprising an auxiliary cylinder, a plunger operating therein, means for actuating said plunger in said auxiliary cylinder, gas escape ports in said plunger, and a float valve on said plunger to close said ports only when said plunger is brought in contact with said liquid.

4. In a iluid pump, means defining a pump chamber, inlet and outlet means for fluid to be pumped communicating with said pump chamber, a column of mercury in said pump chamber constituting a liquid piston reciprocable in said chamber, means for alternately elevating-and depressing said mercury column in said pump chamber to pump uids into and out of said chamber,

and a coating upon the interior walls of said pump chamber formed of material capable of amalgamating with mercury to provide an amalgam coating thereon to prevent fluids to be pumped from adhering to the surfaces of said pump chamber.

5. 1n a fluid pump, means defining a pump chamber, inlet and outlet means for fluid to be pumped communicating with said pump chamber, a column of mercuryy in said pump chamber constituting a liquid piston reciprocable in said chamber, means for alternately elevating and depressing said mercury column in said pump chamber to pump uids into and out of said chamber, a coating upon the interior walls of said pump chamber formed of material capable of amalgamating with mercury to provide an amalgam coating thereon to prevent fluids to be pumped from adhering to the surfaces of Asaid pump chamber, and a similarly coated metallic piston floating uponthe said column of mercury to`reduce the eiective area of said mercury exposed tothe liquidto be pumped.

6. In a fluid pump, means defining a cylinder and a pumpl chamber spaced from each other and interconnected by a fluid passage, a metallic piston reciprocably mounted in said cylinder, inlet and outlet means for uid to be pumped communicating 'with `said pump chamber, a' liquid column interposed Vbetween said metallic piston and said pump chamber including a column of oil adjacent said metallic piston, to provide a bath of lubricant in which said metallic piston operates and to provide a liquid piston in the pump chamber preventing the fluid to be pumped from contacting the metallic piston and its cylinder walls, and force pump means operating upon each cycle of movement of the piston for returning to said oil column during each said cycle any oil which may have leaked past said metallic piston.

7. In a uid pump, means defining a cylinder and a pump chamber spaced from each other and interconnected by a fluid passage, a metallic piston reciprocably mounted in said cylinder, inlet and outlet means for fluid to be pumped communicating with said pump chamber, a liquid column interposed between said metallic piston and said pump chamberincluding a column of oil adjacent said metallic piston, to provide a bath of lubricant in which said metallic piston operates and -to provide a liquid piston in the pump chamber preventing the fluid to be pumped from contacting the metallic piston and its cylinder walls, and a force pump on said piston for returning to said column any liquid which may leak past said metallic piston, said force pump having a volumetric capacity in excess of the maximum volume of leakage on each strokeof said metallic piston to insure return of all the liquid to the column.

8. In a fluid pump, means defining a cylinder and a pump chamber spaced from each other and interconnected by a fluid passage, a metallic piston reciprocably mounted in said cylinder, inlet and outlet means for iluid to be pumped communicating with saidpump chamber, a liquid` column interposed between said metallic piston and said pump chamber including a columnof oil adjacent said metallic piston, to provide a bath of lubricant in which said metallic piston operates and to provide a liquid piston in the pump chamber preventing the fluid to be pumped from contacting ,the metallic piston and vits cylinder walls, and a force pump on said piston for returning to said column any liquid which may leak past said' metallic piston, said force pump comprising an auxiliary cylinder, a plunger operating therein, means for actuating-said lplunger upon each stroke of said metallic piston, gas vescape ports in said plunger and a float valve on said plunger to close said ports only whensaid plunger is brought into contact with liquid.

BENJAMIN F. SCHMIDT. 

